title: Clinical and echocardiographic predictors of nonresponse to cardiac resynchronization therapy.
abstract: BACKGROUND
  Lack of response to cardiac resynchronization therapy (CRT) ranges between 30% to 40% of heart failure (HF) patients. The present study aimed to evaluate the clinical and echocardiographic determinants of nonresponse to CRT.
  
  
  METHODS
  A total of 581 patients (66.4 ± 10.0 years, 77.9% male) with advanced HF scheduled for CRT implantation were included. Clinical and echocardiographic evaluations were performed at baseline and 6 months of follow-up. Nonresponse was defined as no improvement in the New York Heart Association functional class, death from worsening HF or heart transplantation, and <15% reduction in left ventricular (LV) end-systolic volume.
  
  
  RESULTS
  At 6 months of follow-up, 254 patients (44%) did not respond to CRT. The nonresponders were more frequently male (81.9% vs 74.3%, P = .030) and had ischemic cardiomyopathy (69.7% vs 53.2%, P < .001), shorter QRS duration (150.6 ± 29.9 milliseconds vs 156.0 ± 32.5 milliseconds, P = .041), worse New York Heart Association functional class (2.8 ± 0.6 vs 2.7 ± 0.6, P = .008) and shorter 6-minute walk distance (297.9 ± 110.7 m vs 331.8 ± 112.6 m, P = .001), larger left atrial volumes (44.9 ± 16.9 mL/m(2) vs 40.9 ± 17.6 mL/m(2), P = .006), less baseline LV dyssynchrony (56.2 ± 41.3 milliseconds vs 69.1 ± 39.9 milliseconds, P < .001), and, more frequently, anterior LV lead position (12.4% vs 4.0%, P = .007). At multivariate analysis, only the ischemic etiology of HF (odds ratio [OR] 2.264, P = .005), shorter 6-minute walk distance at baseline (OR 0.998, P = .030), less baseline LV dyssynchrony (OR 0.989, P < .001), and anterior LV lead position (OR 3.713, P < .010) remained independent predictors of nonresponse to CRT.
  
  
  CONCLUSIONS
  Ischemic etiology of HF, shorter baseline 6-minute walk distance, less baseline LV dyssynchrony, and anterior LV lead position are independent determinants of nonresponse to CRT.
authors.affiliation: Department of Cardiology, Leiden University Medical Center, The Netherlands.
authors.forename: Miriam
authors.initials: M
authors.lastname: Shanks
authors.forename: Victoria
authors.initials: V
authors.lastname: Delgado
authors.forename: Arnold C T
authors.initials: AC
authors.lastname: Ng
authors.forename: Dominique
authors.initials: D
authors.lastname: Auger
authors.forename: Eline A Q
authors.initials: EA
authors.lastname: Mooyaart
authors.forename: Matteo
authors.initials: M
authors.lastname: Bertini
authors.forename: Nina Ajmone
authors.initials: NA
authors.lastname: Marsan
authors.forename: Rutger J
authors.initials: RJ
authors.lastname: van Bommel
authors.forename: Eduard R
authors.initials: ER
authors.lastname: Holman
authors.forename: Don
authors.initials: D
authors.lastname: Poldermans
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Schalij
authors.forename: Jeroen J
authors.initials: JJ
authors.lastname: Bax
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000209:etiology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017202:Myocardial Ischemia / Q000150:complications; D010138:Pacemaker, Artificial; D017211:Treatment Failure; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging; D020257:Ventricular Remodeling